Tone when writingis the use of <u>specific words</u> that influence the readers and affects the theme of the message.
Please note that your question is incomplete as you did not mention the NPR article and without this, it is impossible to give you the answer. Therefore, I would give you a general overview that should help you.
There are two major types of tone which are negative and positive tone.
Positive tone has to do with the words that are used by an author to show positivity or evoke good feelings. Negative tone on the other hand, is the opposite of positive tone which shows negative feelings.
Some examples of words that evoke positive tone: Happy, Approving, Appreciative, Calm, etc. Some examples of words that evoke negative tone include: Angry, Fearful, Uncertain, etc.
The organizing principles that are used in this paragraph are comparison and contrast; cause and effect. In the beginning, the author is giving the similarities and the differences between petroleum and coal, and moves on to talk about cause and effect in the end.
